Central nervous system involvement in early syphilis. Part II. Correlation between auditory brain stem responses (ABR) and cerebrospinal fluid abnormalities.

Twenty-six consecutive patients with secondary or early latent syphilis, all with normal neurological findings, were studied with auditory brainstem responses (ABR), cerebrospinal fluid (CSF) analysis and an assay for immune complexes in serum and CSF. Seven of the 26 patients studied had a pathological ABR pattern and 14 had one or more pathological CSF tests. Fifteen patients had circulating immune complexes in serum. No patient had demonstrable immune complexes in CSF. A significant correlation was found between an abnormal ABR pattern and pathological CSF findings--but not between pathological ABR and presence of immune complexes. ABR seems to be a sensitive method for detection of early asymptomatic CNS involvement in syphilis.